<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  
  <script>
    // 显式绑定
    var obj = {
      name: "why"
    }

    function foo() {
      console.log("foo函数:", this)
    }

    // 执行函数, 并且函数中的this指向obj对象
    // obj.foo = foo
    // obj.foo()

    // 执行函数, 并且强制this就是obj对象
    foo.call(obj)
    foo.call(123)
    foo.call("abc")

  </script>

</body>
</html>